fix(protocol): restore encoder used for uploaded image message info

The previous envelope cleanup dropped an import that still packs
outgoing image message info, so typecheck and the v1.14.16 release
preflight failed.

packages/protocol/src/highway/pipeline.ts

@@ -10,6 +10,7 @@ import type {
   NTV2UploadInfo,
   NTV2UploadRespBody,
 } from '@snowluma/proto-defs/highway';
+import { protobuf_encode } from '@snowluma/proton';
 import crypto from 'crypto';
 import type { BridgeContext } from '../bridge-context';
 import { OidbError } from '../oidb-service';